When to Prune Hydrangeas (and How) by Type

When to prune hydrangeas depends on which kind you have. Hydrangeas that bloom on old wood (bigleaf, mountain and oakleaf) should be pruned right after their flowers fade in summer, while hydrangeas that bloom on new wood (panicle and smooth) should be pruned in late winter or early spring before new growth starts. Reblooming types can be pruned in early spring or right after their first round of flowers.

Get the timing wrong on an old-wood hydrangea and you can cut off next year's flowers. Here's how to tell which type you have, when and how to cut each one, and what to do if yours didn't bloom.

Old wood vs. new wood: the one idea that matters

"Old wood" means stems that grew last year. "New wood" means stems that grow this spring and summer. Every hydrangea sets its flower buds on one or the other, and that single fact decides your pruning calendar.

• Old-wood bloomers form next year's flower buds in late summer and fall. According to University of Georgia Extension, bigleaf hydrangea "forms its flower buds in late summer for the following year, so pruning in late summer, fall and winter will remove potential flowers."
• New-wood bloomers make their flowers on stems that grow during the current season. Clemson Cooperative Extension notes that panicle and smooth hydrangeas "develop flowers on new wood produced during the current growing season," so a spring haircut doesn't cost you blooms.
• Rebloomers flower on both old and new wood. If the old-wood buds are lost, new stems can still bloom later in the summer.

As Clemson puts it, "It is essential to know which species or cultivar you have to determine when to prune."

How to tell which hydrangea you have

If you still have the plant tag, the name usually tells you. If not, the leaves and flowers give it away:

• Bigleaf (mophead or lacecap): large, glossy, rounded leaves; flowers are round balls (mopheads) or flat discs ringed with bigger petals (lacecaps). Often blue, pink or purple.
• Mountain: looks like a smaller bigleaf with narrower, more pointed leaves; usually lacecap flowers.
• Oakleaf: leaves shaped like a large oak leaf, with strong fall color.
• Panicle: cone-shaped flower clusters that open white or green and often age to pink or red. Can be grown as a shrub or a small single-trunk tree.
• Smooth: thin, soft stems and big rounded white (sometimes pink) heads. 'Annabelle' is the classic example.
• Climbing: a woody vine that clings to walls, fences or tree trunks, with flat white flower clusters.

When to prune each type of hydrangea

Bigleaf hydrangeas (mophead and lacecap)

When: Right after the flowers fade in summer. University of Georgia Extension advises not pruning bigleaf hydrangeas after August 1, and University of Minnesota Extension says to make heading cuts before August.

How: Clemson recommends removing no more than about a third of the plant's total growth. Cut spent flower stems back to a pair of healthy buds. In spring, University of New Hampshire Extension suggests waiting until growth appears, then cutting dead stems back to about ¼ inch above live buds. Their tip: "Stems with live buds will be green on the inside, while dead stems will be brown."

From our catalog, Tilt-A-Swirl® Bigleaf Hydrangea falls in this group.

Reblooming bigleaf hydrangeas (like Endless Summer)

When: Early spring, or right after the first flush of flowers fades. University of Maryland Extension says reblooming types can be pruned "either in early spring or after the first flush of flowers has faded," and Clemson recommends pruning Endless Summer right after its first bloom.

Why they're forgiving: University of Minnesota Extension notes that Endless Summer varieties "bloom on old and new wood." University of Maryland adds a fair warning: pruning early can delay flowering, and cutting in midseason may shorten the rebloom window. So go light.

Reblooming bigleaf hydrangeas in our catalog include Endless Summer® Hydrangea, Cherry-Go-Round® Reblooming Hydrangea, Frill Ride® Reblooming Hydrangea and Grin and Tonic™ Reblooming Hydrangea.

Mountain hydrangeas

When: Treat them like bigleaf hydrangeas. University of Maryland Extension says to prune "just after the flowers fade." University of New Hampshire Extension notes mountain hydrangeas are similar to bigleaf but slightly more winter hardy, and advises leaving stems alone until spring, when you can see which buds are alive.

Example: Pink Dynamo™ Mountain Hydrangea.

Oakleaf hydrangeas

When: Soon after flowering, and only if needed. Clemson says oakleaf hydrangeas bloom in June on old wood and can be pruned soon after flowering to keep a desired height and shape. University of New Hampshire Extension says they need minimal pruning; just remove dead or damaged branches in spring.

Panicle hydrangeas

When: Late winter or early spring, before the leaves come out. University of Maryland Extension and University of New Hampshire Extension both recommend this window. University of Minnesota Extension says panicle hydrangeas can technically be cut in fall, too, but recommends "leaving the dry, tan flower heads on the plant to provide some winter interest."

How: Cut stems back to just above a fat bud. University of Minnesota calls this a heading cut, made about ¼ inch above the bud. Panicles can be cut back fairly hard, or left taller for a bigger plant. University of Maryland notes they can also be kept as a single-trunk "standard," or tree form.

Panicle hydrangeas in our catalog include Vanilla Strawberry™ Hydrangea, Dragon Baby™ Hardy Hydrangea and the tree-form Quick Fire® Hydrangea Tree.

Smooth hydrangeas (Annabelle types)

When: Late winter or early spring. These are the easiest to prune. University of New Hampshire Extension says smooth hydrangeas "bloom on new wood and will tolerate heavy pruning."

How: Once the plant is established, University of Minnesota Extension says you can cut smooth hydrangeas down to the ground in spring. University of Maryland suggests about 12 inches from the ground. If you'd rather have a bigger shrub, Minnesota says you can skip pruning entirely.

Example: Incrediball® Hydrangea, a smooth hydrangea in the Annabelle family.

Climbing hydrangeas

When: Rarely. The Morton Arboretum says "little pruning is required, but if necessary to control size, prune in late winter." They also note that growth is slow for the first three to five years and new plants "may take several years to bloom," so patience pays off more than pruning. A related option: Barbara Ann Climbing Hydrangea is a selection of woodvamp (Decumaria barbara), a native climbing cousin of the climbing hydrangea described above.

Quick pruning calendar

• Late winter to early spring: panicle, smooth, climbing (if needed), and light cleanup of rebloomers. Remove dead stems on bigleaf and mountain types once you can see live buds.
• Early to midsummer, right after flowering: bigleaf, mountain, oakleaf, and rebloomers after their first flush.
• After early August: stop pruning old-wood types.
• Fall: mostly hands off. See the next section.

How to prune hydrangeas, step by step

1. Identify the type using the tag or the clues above.
2. Use clean, sharp bypass pruners (the scissor-style kind) so cuts are clean.
3. Remove dead wood first. Scratch a stem lightly: green underneath means alive, brown means dead.
4. Make heading cuts about ¼ inch above a healthy bud or pair of buds.
5. Thin crowded plants by removing a few of the oldest, weakest stems at the base. University of Maryland Extension notes that pruning to improve air circulation can reduce disease.
6. Don't overdo it on old-wood types. Stick to about a third of the plant at most, per Clemson.

Should you cut hydrangeas back in fall?

For most hydrangeas, no. For old-wood types, fall cutting removes the flower buds that formed in late summer; University of Georgia Extension warns that pruning bigleaf hydrangeas in late summer, fall or winter "will remove potential flowers." For panicles, University of Minnesota Extension suggests leaving the dried flower heads for winter interest, and University of Maryland and New Hampshire both point to late winter or early spring as the best time.

The one easy exception: smooth hydrangeas bloom on new wood, so snipping off their spent flowers in fall won't cost you next year's blooms.

Fall is, however, a great time to plant hydrangeas. Here's why fall is the best time to plant trees and shrubs.

Why didn't my hydrangea bloom?

University of Georgia Extension names four main reasons bigleaf hydrangeas fail to flower: "Winter injury to the flower buds, growing the plant in too much shade, applying excess nitrogen fertilizer, or pruning at the wrong time of year." Here's how to sort it out:

• Pruned at the wrong time. Cutting an old-wood hydrangea in late summer, fall, winter or early spring removes its buds. Prune right after flowering instead.
• Winter killed the buds. Old-wood buds can be damaged by cold even when the plant survives. University of New Hampshire Extension suggests protecting bigleaf plants with a mesh cylinder filled with leaves, or choosing a reblooming variety that can still flower on new growth.
• Too much shade. Hydrangeas like some shade, but too little sun cuts down on flowers.
• Too much nitrogen fertilizer. Heavy feeding, including lawn fertilizer that drifts into beds, pushes leaves instead of flowers.
• A hard renewal cut. University of Maryland Extension notes that heavy rejuvenation pruning can keep a hydrangea from flowering for a season or more while it recovers.

Panicle and smooth hydrangeas almost never have this problem. University of New Hampshire Extension says panicles flower "reliably season to season."

Not sure which hydrangeas are hardy where you live? Your USDA hardiness zone (a number based on your area's average coldest winter temperature) is the quickest check. Use our growing zone guide to find yours.

Common questions

Can I prune hydrangeas in spring?

Yes for panicle and smooth hydrangeas, which bloom on new wood. For bigleaf, mountain and oakleaf types, limit spring pruning to removing dead stems once you can see which buds are alive.

What happens if I prune hydrangeas at the wrong time?

On new-wood types, usually nothing. On old-wood types, you'll likely lose that year's flowers, but the plant itself will be fine. Rebloomers may still flower later in summer on new stems.

Should I deadhead hydrangeas?

It's optional. University of Maryland Extension lists removing spent flowers as an optional task. On rebloomers, snipping faded flowers just below the head is a light way to tidy up.

How far back can I cut a hydrangea?

Smooth hydrangeas can go to the ground or about 12 inches. Panicles can be cut back fairly hard to a fat bud. Old-wood types should lose no more than about a third of their growth.

Find your next hydrangea

Want a hydrangea that's hard to prune wrong? Panicle, smooth and reblooming types are the most forgiving. Browse our full hydrangea collection to compare types, sizes and sun needs.

Sources and further reading

• Pruning Hydrangeas, University of Maryland Extension
• Pruning Hydrangeas, Clemson Cooperative Extension Home & Garden Information Center
• Pruning Hydrangeas, University of Minnesota Extension
• When to Prune Hydrangeas for Best Bloom, University of Minnesota Extension
• Pruning Hydrangeas Fact Sheet, University of New Hampshire Extension
• Growing Bigleaf Hydrangea, University of Georgia Extension
• Climbing Hydrangea, The Morton Arboretum